Dispersion Characteristic and Its Effect of High Refractive Index Glass Beads
高折射率玻璃微珠色散特性及影响

Based on the secondary rainbow principle, three kinds of glass beads with typical refractive indices 1.90, 1.93 and 2.2 are measured by semiconductor lasers with three different wavelengths (632.8 nm, 532 nm and 404 nm). Then dispersion functions are determined according to Cauchy function and experimental results, which show that the normal dispersion characteristic belongs to the glass beads but with the large amount. By analyzing whether the dispersion has effect on retroreflective capability with different incident angles from 0° to 90°, it shows that the retroreflective capability of glass beads with refractive index 2.2 is inferior to those of 1.90 and 1.93. Additionally, the energy distribution of retroreflect lights in the paraxial region is simulated by ray tracing method. And the results indicate that the retroreflective energies of glass beads with refractive indices 1.90 and 1.93 are mainly concentrated in the range of 5°.